70 research outputs found
Biot-Savart-like law in electrostatics
The Biot-Savart law is a well-known and powerful theoretical tool used to
calculate magnetic fields due to currents in magnetostatics. We extend the
range of applicability and the formal structure of the Biot-Savart law to
electrostatics by deriving a Biot-Savart-like law suitable for calculating
electric fields. We show that, under certain circumstances, the traditional
Dirichlet problem can be mapped onto a much simpler Biot-Savart-like problem.
We find an integral expression for the electric field due to an arbitrarily
shaped, planar region kept at a fixed electric potential, in an otherwise
grounded plane. As a by-product we present a very simple formula to compute the
field produced in the plane defined by such a region. We illustrate the
usefulness of our approach by calculating the electric field produced by planar
regions of a few nontrivial shapes.Comment: 14 pages, 6 figures, RevTex, accepted for publication in the European
Journal of Physic
S3 guidelines for intensive care in cardiac surgery patients: hemodynamic monitoring and cardiocirculary system
Hemodynamic monitoring and adequate volume-therapy, as well as the treatment with positive inotropic drugs and vasopressors are the basic principles of the postoperative intensive care treatment of patient after cardiothoracic surgery. The goal of these S3 guidelines is to evaluate the recommendations in regard to evidence based medicine and to define therapy goals for monitoring and therapy. In context with the clinical situation the evaluation of the different hemodynamic parameters allows the development of a therapeutic concept and the definition of goal criteria to evaluate the effect of treatment
An overview of the mid-infrared spectro-interferometer MATISSE: science, concept, and current status
MATISSE is the second-generation mid-infrared spectrograph and imager for the
Very Large Telescope Interferometer (VLTI) at Paranal. This new interferometric
instrument will allow significant advances by opening new avenues in various
fundamental research fields: studying the planet-forming region of disks around
young stellar objects, understanding the surface structures and mass loss
phenomena affecting evolved stars, and probing the environments of black holes
in active galactic nuclei. As a first breakthrough, MATISSE will enlarge the
spectral domain of current optical interferometers by offering the L and M
bands in addition to the N band. This will open a wide wavelength domain,
ranging from 2.8 to 13 um, exploring angular scales as small as 3 mas (L band)
/ 10 mas (N band). As a second breakthrough, MATISSE will allow mid-infrared
imaging - closure-phase aperture-synthesis imaging - with up to four Unit
Telescopes (UT) or Auxiliary Telescopes (AT) of the VLTI. Moreover, MATISSE
will offer a spectral resolution range from R ~ 30 to R ~ 5000. Here, we
present one of the main science objectives, the study of protoplanetary disks,
that has driven the instrument design and motivated several VLTI upgrades
(GRA4MAT and NAOMI). We introduce the physical concept of MATISSE including a
description of the signal on the detectors and an evaluation of the expected
performances. We also discuss the current status of the MATISSE instrument,
which is entering its testing phase, and the foreseen schedule for the next two
years that will lead to the first light at Paranal.Comment: SPIE Astronomical Telescopes and Instrumentation conference, June
2016, 11 pages, 6 Figure
Innovative Crop Productions for Healthy Food: The Case of Chia (Salvia hispanica L.)
Chia (Salvia hispanica L.) is an ancient crop from Central America
which has been recently rediscovered as a source of ω-3 and nutraceuticals in
seeds. Besides traditional seed consumption, innovative uses of the plant seeds
and leaves have been proposed based on the high protein content and the production
of mucilage which lends itself to a range of applications. This chapter reviews
research on the plant’s genetics and breeding, quality, and uses. Agronomic studies
which have only recently started worldwide are also presented along with results
from case studies in Basilicata
Dopamine Modulates Persistent Synaptic Activity and Enhances the Signal-to-Noise Ratio in the Prefrontal Cortex
The importance of dopamine (DA) for prefrontal cortical (PFC) cognitive functions is widely recognized, but its mechanisms of action remain controversial. DA is thought to increase signal gain in active networks according to an inverted U dose-response curve, and these effects may depend on both tonic and phasic release of DA from midbrain ventral tegmental area (VTA) neurons.We used patch-clamp recordings in organotypic co-cultures of the PFC, hippocampus and VTA to study DA modulation of spontaneous network activity in the form of Up-states and signals in the form of synchronous EPSP trains. These cultures possessed a tonic DA level and stimulation of the VTA evoked DA transients within the PFC. The addition of high (≥1 µM) concentrations of exogenous DA to the cultures reduced Up-states and diminished excitatory synaptic inputs (EPSPs) evoked during the Down-state. Increasing endogenous DA via bath application of cocaine also reduced Up-states. Lower concentrations of exogenous DA (0.1 µM) had no effect on the up-state itself, but they selectively increased the efficiency of a train of EPSPs to evoke spikes during the Up-state. When the background DA was eliminated by depleting DA with reserpine and alpha-methyl-p-tyrosine, or by preparing corticolimbic co-cultures without the VTA slice, Up-states could be enhanced by low concentrations (0.1–1 µM) of DA that had no effect in the VTA containing cultures. Finally, in spite of the concentration-dependent effects on Up-states, exogenous DA at all but the lowest concentrations increased intracellular current-pulse evoked firing in all cultures underlining the complexity of DA's effects in an active network.Taken together, these data show concentration-dependent effects of DA on global PFC network activity and they demonstrate a mechanism through which optimal levels of DA can modulate signal gain to support cognitive functioning
An investigation into aripiprazole's partial D(2) agonist effects within the dorsolateral prefrontal cortex during working memory in healthy volunteers
Rationale:
Working memory impairments in schizophrenia have been attributed to dysfunction of the dorsolateral prefrontal cortex (DLPFC) which in turn may be due to low DLPFC dopamine innervation. Conventional antipsychotic drugs block DLPFC D2 receptors, and this may lead to further dysfunction and working memory impairments. Aripiprazole is a D2 receptor partial agonist hypothesised to enhance PFC dopamine functioning, possibly improving working memory.
Objectives:
We probed the implications of the partial D2 receptor agonist actions of aripiprazole within the DLPFC during working memory. Investigations were carried out in healthy volunteers to eliminate confounds of illness or medication status. Aripiprazole’s prefrontal actions were compared with the D2/5-HT2A blocker risperidone to separate aripiprazole’s unique prefrontal D2 agonist actions from its serotinergic and striatal D2 actions that it shares with risperidone.
Method:
A double-blind, placebo-controlled, parallel design was implemented. Participants received a single dose of either 5 mg aripiprazole, 1 mg risperidone or placebo before performing the n-back task whilst undergoing fMRI scanning.
Results:
Compared with placebo, the aripiprazole group demonstrated enhanced DLPFC activation associated with a trend for improved discriminability (d’) and speeded reaction times. In contrast to aripiprazole’s neural effects, the risperidone group demonstrated a trend for reduced DLPFC recruitment. Unexpectedly, the risperidone group demonstrated similar effects to aripiprazole on d’ and additionally had reduced errors of commission compared with placebo.
Conclusion:
Aripiprazole has unique DLPFC actions attributed to its prefrontal D2 agonist action. Risperidone’s serotinergic action that results in prefrontal dopamine release may have protected against any impairing effects of its prefrontal D2 blockade
Outpatient high-dose chemotherapy with autologous stem-cell rescue for hematologic and nonhematologic malignancies.
5-fluorocytosine susceptibility of pathogenic fungi in the presence of allopurinol: potential for improving the therapeutic index of 5-fluorocytosine
A double-blind, randomized, placebo-controlled phase II study of the steroidal aromatase inhibitor exemestane with and without the isoform selective histone deacetylase inhibitor (HDACi) entinostat in metastatic breast cancer (MBC).
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